The research funded by this grant is aimed at acquiring a better understanding of the normal processes of human hearing, especially of binaural hearing. Recent efforts have been concentrated on the functioning of the high-frequency segments of the binaural auditory system, namely on how interaural differences in arrival time are utilized by these segments. Both sound-localization and signal-detection tasks have been used. The important outcome is that the system can be just as sensitive to interaural time differences at high frequencies as it is at low--only a few tens of microseconds are necessary for good performance. BIBLIOGRAPHIC REFERENCES: McFadden, D., Reply to J.C. Stevens. Journal of the Acoustical Society of America, 1976, 59, 473-474. McFadden, D., and Pasanen, E.G. Lateralization at high frequencies based on interaural time differences. Journal of the Acoustical Society of America, Vol. 59, No. 3, March 1976, 634-639.